Dark clots during your period are thick, jelly-like masses of blood that form when menstrual flow slows or pools in the vagina. They're most common during heavy periods, especially in people who have given birth.
Clots develop when blood doesn't exit the uterus quickly enough. The longer blood stays inside, the darker and thicker it becomes due to exposure to air and enzymes. This is why clots often appear at the start or end of a period, when flow is lighter.
| Type | Appearance | Common Causes |
|---|---|---|
| Bright red clots | Soft, jelly-like | Heavy flow, recent birth |
| Dark clots | Firm, coffee-ground texture | Slower flow, hormonal changes |
| Stringy clots | Long, fibrous strands | Endometrial tissue shedding |
Dark clots are usually harmless, especially if your period is regular and not excessively heavy. For example, many people notice darker clots when they wake up after sleeping on their backs, which slows flow. However, consistently passing large clots (bigger than a quarter) or experiencing extreme cramping may warrant a visit to a healthcare provider.
Consult a doctor if dark clots accompany:
These symptoms could indicate conditions like fibroids, endometriosis, or hormonal imbalances. A doctor can rule out underlying issues and recommend treatments like birth control or lifestyle changes.